Is the Sagrada Familia being banalised in the name of tourism?

Antoni Gaudí was the most modern and the most medieval of souls. The great Catalan architect, whose ecstatic, organic vision has made his buildings among the world's best-loved, saw himself as recreating a Christian society through art. What makes him so great is that his architecture expresses that longing with no regard for convention and no tyranny of tradition, and with such an enthusiasm for the techniques and fragments of modern life - the shards of mosaic on his facades, the dynamism of his interiors - that it becomes an art of energy and change even as it wishes for order. Gaudí's genius is inexhaustibly rich. But has it been betrayed?

A group of Spanish architects and art world types has savagely denounced the continuing work to complete Gaudí's religious masterpiece the Sagrada Familia. Should work on this vast church - often mistaken, with good reason, for Barcelona's cathedral – have been carried on, after his death in 1926 left it unfinished? The grumpy intellectuals say no. Gaudí, they complain, is being banalised in the name of tourism.

It's true that a lot of tourists go to the Sagrada Familia. Last time I was there, some English blokes on a stag weekend stood staring up bleary-eyed at the crazed plenitudes of the building's Victor Hugo fantasia of a facade - the section of the building that Gaudí himself brought closest to completion. It's probably not the best thing to look at with a hangover. But what is wrong with Gaudí's popularity? Nothing. He was an architect with a generous social vision and it is fitting that his works are visited. It is so rare for an architect to be truly loved that to carp at the masses who go to see Gaudí is a quite nasty form of snobbery.

But what about the specific question of the drive to finish the church? Work there has carried on, sporadically, since 1926. In other words the completion effort predates Gaudí's contemporary fame. I personally find it moving. Anyone can see that the interior is not by Gaudí and never will be: however closely based on his designs, it does not have his touch. Obviously. The collective work, however, has the poetry of an architectural spectacle more medieval than modern - the century-long effort to build a great cathedral. These critics need to read their Ruskin. Far from betraying Gaudí's spirit, the belief that the Sagrada Familia should be finished is in accord with a religious sensibility in which the architect is a worker, not a star.

Michelangelo, another great religious architect, designed the dome of St Peter's but died before he could erect it. His designs were adapted by later architects. Does this make St Peter's a botched job, a betrayal? No. We experience it for what it is - a great collective religious work in which the individual contributions of Michelangelo, Bramante, Raphael, Sangallo and Bernini are visible, yet at the same time subsumed in the common purpose.

Significantly, Michelangelo for once set aside his habitual rivalries at St Peter's and incorporated into his own contribution designs by his enemy Bramante. This was the place to work together, not against one another.

That ancient attitude to building churches - which can also be experienced at Salisbury Cathedral, or Notre Dame, or Cologne - is kept alive today by the pious effort to finish Gaudí's masterpiece. I love the emerging result, kitsch and all.